netdev - Re: [PATCH] net: rfkill-regulator: Add devicetree support.

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Message-ID: <20140210101842.GS25314@e106331-lin.cambridge.arm.com>
Date:	Mon, 10 Feb 2014 10:18:42 +0000
From:	Mark Rutland <mark.rutland@....com>
To:	Marek Belisko <marek@...delico.com>
Cc:	"robh+dt@...nel.org" <robh+dt@...nel.org>,
	Pawel Moll <Pawel.Moll@....com>,
	"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
	"galak@...eaurora.org" <galak@...eaurora.org>,
	"rob@...dley.net" <rob@...dley.net>,
	"linville@...driver.com" <linville@...driver.com>,
	"johannes@...solutions.net" <johannes@...solutions.net>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"grant.likely@...aro.org" <grant.likely@...aro.org>,
	"neilb@...e.de" <neilb@...e.de>,
	"hns@...delico.com" <hns@...delico.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH] net: rfkill-regulator: Add devicetree support.

On Fri, Feb 07, 2014 at 07:48:49PM +0000, Marek Belisko wrote:
> Signed-off-by: NeilBrown <neilb@...e.de>
> Signed-off-by: Marek Belisko <marek@...delico.com>
> ---
> Based on Neil's patch and extend for documentation and bindings include.
> 
>  .../bindings/net/rfkill/rfkill-relugator.txt       | 28 ++++++++++++++++
>  include/dt-bindings/net/rfkill-regulator.h         | 23 +++++++++++++
>  net/rfkill/rfkill-regulator.c                      | 38 ++++++++++++++++++++++
>  3 files changed, 89 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/rfkill/rfkill-relugator.txt
>  create mode 100644 include/dt-bindings/net/rfkill-regulator.h
> 
> diff --git a/Documentation/devicetree/bindings/net/rfkill/rfkill-relugator.txt b/Documentation/devicetree/bindings/net/rfkill/rfkill-relugator.txt
> new file mode 100644
> index 0000000..cdb7dd7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/rfkill/rfkill-relugator.txt
> @@ -0,0 +1,28 @@
> +Regulator consumer for rfkill devices

What exactly is an "rfkill" device? How is it used? How does it relate
to other devices in the DT?

To me, this looks like a leak of a Linux abstraction.

> +
> +Required properties:
> +- compatible   : Must be "rfkill-regulator".
> +- label  : Name of rfkill device.

What's this for? Why does this need a label in the DT? Surely this can
be implied by the relationship to a particular radio device?

> +- type  : Type of rfkill device.
> +
> +Possible values (defined in include/dt-bindings/net/rfkill-regulator.h):
> +	RFKILL_TYPE_ALL
> +	RFKILL_TYPE_WLAN
> +	RFKILL_TYPE_BLUETOOTH
> +	RFKILL_TYPE_UWB
> +	RFKILL_TYPE_WIMAX
> +	RFKILL_TYPE_WWAN
> +	RFKILL_TYPE_GPS
> +	RFKILL_TYPE_FM
> +	RFKILL_TYPE_NFC

What do these mean? Why can these not be implied by a relationship to
any devices of these particular types?

> +
> +- vrfkill-supply - regulator device.

Why isn't this described on the radio revice node? It's a supply to the
radio, not to the rfkill concept.

> +
> +Example:
> +	gps-rfkill {
> +		compatible = "rfkill-regulator";
> +		label = "GPS";
> +		type = <RFKILL_TYPE_GPS>;
> +		vrfkill-supply = <&reg>;
> +	};

Why is this not bound to the particular GPS device in some way?

What if I have more than one of any of the types of device this
supports, which device is this expected to control?

Why is it described as a separate device in the device tree at all?

I do not think this binding is the right way to describe this.

Thanks,
Mark.

> +
> diff --git a/include/dt-bindings/net/rfkill-regulator.h b/include/dt-bindings/net/rfkill-regulator.h
> new file mode 100644
> index 0000000..ae32273
> --- /dev/null
> +++ b/include/dt-bindings/net/rfkill-regulator.h
> @@ -0,0 +1,23 @@
> +/*
> + * This header provides macros for rfkill-regulator bindings.
> + *
> + * Copyright (C) 2014 Marek Belisko <marek@...delico.com>
> + *
> + * GPLv2 only
> + */
> +
> +#ifndef __DT_BINDINGS_RFKILL_REGULATOR_H__
> +#define __DT_BINDINGS_RFKILL_REGULATOR_H__
> +
> +
> +#define RFKILL_TYPE_ALL		(0)
> +#define RFKILL_TYPE_WLAN	(1)
> +#define RFKILL_TYPE_BLUETOOTH	(2)
> +#define RFKILL_TYPE_UWB		(3)
> +#define RFKILL_TYPE_WIMAX	(4)
> +#define RFKILL_TYPE_WWAN	(5)
> +#define RFKILL_TYPE_GPS		(6)
> +#define RFKILL_TYPE_FM		(7)
> +#define RFKILL_TYPE_NFC		(8)
> +
> +#endif /* __DT_BINDINGS_RFKILL_REGULATOR_H__ */
> diff --git a/net/rfkill/rfkill-regulator.c b/net/rfkill/rfkill-regulator.c
> index cf5b145..a04aff8 100644
> --- a/net/rfkill/rfkill-regulator.c
> +++ b/net/rfkill/rfkill-regulator.c
> @@ -19,6 +19,7 @@
>  #include <linux/regulator/consumer.h>
>  #include <linux/rfkill.h>
>  #include <linux/rfkill-regulator.h>
> +#include <linux/of_platform.h>
>  
>  struct rfkill_regulator_data {
>  	struct rfkill *rf_kill;
> @@ -57,6 +58,31 @@ static struct rfkill_ops rfkill_regulator_ops = {
>  	.set_block = rfkill_regulator_set_block,
>  };
>  
> +#ifdef CONFIG_OF
> +static struct rfkill_regulator_platform_data *
> +rfkill_regulator_parse_pdata(struct device *dev)
> +{
> +	struct rfkill_regulator_platform_data *pdata;
> +	struct device_node *np = dev->of_node;
> +	u32 num;
> +	if (!np)
> +		return NULL;
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return NULL;
> +	if (of_property_read_u32(np, "type", &num) == 0)
> +		pdata->type = num;
> +	of_property_read_string(np, "label", &pdata->name);
> +	return pdata;
> +}
> +#else
> +static inline struct rfkill_regulator_platform_data *
> +rfkill_regulator_parse_pdata(struct device *dev)
> +{
> +	return NULL;
> +}
> +#endif
> +
>  static int rfkill_regulator_probe(struct platform_device *pdev)
>  {
>  	struct rfkill_regulator_platform_data *pdata = pdev->dev.platform_data;
> @@ -65,6 +91,9 @@ static int rfkill_regulator_probe(struct platform_device *pdev)
>  	struct rfkill *rf_kill;
>  	int ret = 0;
>  
> +	if (!pdata)
> +		pdata = rfkill_regulator_parse_pdata(&pdev->dev);
> +
>  	if (pdata == NULL) {
>  		dev_err(&pdev->dev, "no platform data\n");
>  		return -ENODEV;
> @@ -137,12 +166,21 @@ static int rfkill_regulator_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_OF
> +static const struct of_device_id rfkill_regulator_match[] = {
> +	{.compatible = "rfkill-regulator"},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, rfkill_regulator_match);
> +#endif
> +
>  static struct platform_driver rfkill_regulator_driver = {
>  	.probe = rfkill_regulator_probe,
>  	.remove = rfkill_regulator_remove,
>  	.driver = {
>  		.name = "rfkill-regulator",
>  		.owner = THIS_MODULE,
> +		.of_match_table = of_match_ptr(rfkill_regulator_match),
>  	},
>  };
>  
> -- 
> 1.8.3.2
> 
> 
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